Although fuel is fairly inexpensive today, we know it won't always be that way, so we collected mpg numbers from two of our head-to-head comparison legs of travel. The first was very flat, while the other was more mountainous.

Our Impressions

Going into the drive, the 2015 Ram 1500 Rebel was the favorite given its higher EPA-estimated ratings, and it did not disappoint, winning the first leg handily, but barely squeaking out a win on the second. In both cases, the Ram outperformed the 2015 Toyota Tundra TRD Pro, but it's worth noting that the Tundra outperformed its EPA highway mileage rating on the first longer, flat mileage drive. When looking at the total fuel economy for both drives, the Tundra matched its EPA-estimated combined city/highway rating of 15 mpg; however, the Rebel fell just short of its predicted 17 mpg combined, mostly because it drank so heavily on our second mileage leg.

For two trucks that are similar in weight, horsepower and engine displacement (both have 5.7-liter V-8s), we found there were a few factors that helped tip the scales in favor of the Rebel.

The Rebel comes with an air suspension that drops it more than an inch from its normal ride height into a lower "Aero" mode at highway speeds (between 62 and 65.9 mph for at least 20 seconds or faster than 66 mph). There is no way to manually enter this mode; it activates at speed. During long stretches of open road, that provides a huge benefit.

The differing tread patterns of the all-terrain tires on each truck probably had an effect as well. The Rebel's Toyo Open Country tires have more longitudinal tread patterns, which are more friendly to street driving, while the Tundra's BFG All-Terrains have a more "crisscross," or zigzag pattern, designed for grabbing dirt and rocks.

How We Did the Testing

During each of the driving sections we did our best to hold as many variables constant between the two trucks as we could. We had the windows rolled up, the air conditioning on and both pickups were shifted into Drive for the duration; cruise control was not used.

We swapped drivers halfway through each leg to account for differences in weight and driving styles, and maintained a comfortable speed near posted speed limits on all roads.

After our initial fill-up, once we arrived at our destination each truck was filled from the same pump, using a two-click method to ensure accuracy (after the initial automatic click-off, we manually filled the tank, waiting for the pump to click off automatically one more time). We also used regular 87-octane gasoline and filled the tires to the manufacturer's recommended settings.

One final note: All of our mpg calculations were done using each truck's odometer readouts. To calculate fuel economy, we used each truck's odometer readout and the exact amount of fuel pumped. During each mileage leg, each truck drove the exact same route over the same distance.

Pretty impressive the ram can still crack 20 mpg with those tires and higher ride height.

Posted by: Andre | Oct 19, 2015 10:44:22 AM

the mileage on the Tundra will be incorrect! those tires are taller than the tires that belong on the truck and weigh more. therefore the mileage estimates are incorrect............... that truck should have a 275/65/18 32.1 inch tall tire and that is a 285/70/17 which is 32.7 inch

Posted by: hemi lol | Oct 19, 2015 11:55:32 AM

The MT test also showed all but the same fuel econ for their test. The cruising economy for the ram is certainly cool though. The 2nd leg proves out that it just takes a certain amount of fuel to haul around a big, heavy truck (both truck weigh about the same), no matter how many gears, valves, cams, spark plugs, and collapsing lifters you have.

Posted by: Mr Knowitall | Oct 19, 2015 12:33:29 PM

@hemi lol
Did they say somewhere that they changed the tires?
I would imagine if they came from the factory, the computer is programmed to that tire size.

Posted by: Voltage | Oct 19, 2015 2:28:59 PM

If I remember right, the TRD Pro comes with special Michelin AT tires.

Posted by: uh huh | Oct 19, 2015 2:54:11 PM

I would also think the testers don't use the speedometer reading for mpg testing.

The Ram and Tundra would be different.

Posted by: Big Al from Oz | Oct 19, 2015 3:14:42 PM

Did MT take both trucks to a gas station and top them off after each leg to verify computer read outs/ vs gallons consumed?They should of....

Posted by: ridefoxone | Oct 19, 2015 5:02:39 PM

The Tundra was running optional forged wheels and BFG tires. I run the KO2s on my Tundra--they dropped my MPG by ~1.5 from the stock tires.

Posted by: Dav | Oct 19, 2015 5:15:15 PM

No real comment here for me as I believe they're both too thirsty. That said, for on-road use the Rebel does appear the better choice.

As for some of the following commentary, it seems one or two writers need to read the article again; their questions were very clearly answered.

Yes because I want the big tires and all the off roady stuff on my big heavy V8 do anything (except for haul cargo for the fiat) go anywhere truck and I want to agonize over a 1 to 2 MPG difference. If mileage matters you make different selections in make or model or options or all 3.

Posted by: Clint | Oct 20, 2015 10:34:33 AM

Yes because I want the big tires and all the off roady stuff on my big heavy V8 do anything (except for haul cargo for the fiat) go anywhere truck and I want to agonize over a 1 to 2 MPG difference. If mileage matters you make different selections in make or model or options or all 3.
-- Posted by: Clint | Oct 20, 2015 10:34:33 AM

Which is why I own a '97 Ranger that gives me at least 24mpg highway and a hair under 20mpg mixed.